Exactly as the title says Sapphire Dual-X R9 270X won't work in Z77 Sabertooth PCI-e x16 Slot . I have the latest BIOS update. I also tried to change the PCI slot in BIOS but everytime I get the loading screen for windows 8 but the login screen is just black. Tried all three PCI-e 3.0 slots but only the bottom one works for some reason. Please help